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369 lines
9.6 KiB
369 lines
9.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG |
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#include <linux/memblock.h> |
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#endif |
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#include <linux/cpu.h> |
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#include <linux/kexec.h> |
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#include <linux/slab.h> |
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#include <xen/xen.h> |
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#include <xen/features.h> |
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#include <xen/page.h> |
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#include <asm/xen/hypercall.h> |
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#include <asm/xen/hypervisor.h> |
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#include <asm/cpu.h> |
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#include <asm/e820/api.h> |
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#include "xen-ops.h" |
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#include "smp.h" |
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#include "pmu.h" |
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EXPORT_SYMBOL_GPL(hypercall_page); |
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/* |
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* Pointer to the xen_vcpu_info structure or |
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* &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info |
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* and xen_vcpu_setup for details. By default it points to share_info->vcpu_info |
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* but if the hypervisor supports VCPUOP_register_vcpu_info then it can point |
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* to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to |
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* acknowledge pending events. |
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* Also more subtly it is used by the patched version of irq enable/disable |
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* e.g. xen_irq_enable_direct and xen_iret in PV mode. |
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* |
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* The desire to be able to do those mask/unmask operations as a single |
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* instruction by using the per-cpu offset held in %gs is the real reason |
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* vcpu info is in a per-cpu pointer and the original reason for this |
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* hypercall. |
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* |
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*/ |
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DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); |
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/* |
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* Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info |
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* hypercall. This can be used both in PV and PVHVM mode. The structure |
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* overrides the default per_cpu(xen_vcpu, cpu) value. |
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*/ |
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DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); |
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/* Linux <-> Xen vCPU id mapping */ |
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DEFINE_PER_CPU(uint32_t, xen_vcpu_id); |
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EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); |
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enum xen_domain_type xen_domain_type = XEN_NATIVE; |
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EXPORT_SYMBOL_GPL(xen_domain_type); |
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unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; |
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EXPORT_SYMBOL(machine_to_phys_mapping); |
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unsigned long machine_to_phys_nr; |
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EXPORT_SYMBOL(machine_to_phys_nr); |
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struct start_info *xen_start_info; |
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EXPORT_SYMBOL_GPL(xen_start_info); |
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struct shared_info xen_dummy_shared_info; |
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__read_mostly int xen_have_vector_callback; |
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EXPORT_SYMBOL_GPL(xen_have_vector_callback); |
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/* |
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* NB: needs to live in .data because it's used by xen_prepare_pvh which runs |
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* before clearing the bss. |
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*/ |
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uint32_t xen_start_flags __section(".data") = 0; |
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EXPORT_SYMBOL(xen_start_flags); |
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/* |
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* Point at some empty memory to start with. We map the real shared_info |
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* page as soon as fixmap is up and running. |
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*/ |
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struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; |
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/* |
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* Flag to determine whether vcpu info placement is available on all |
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* VCPUs. We assume it is to start with, and then set it to zero on |
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* the first failure. This is because it can succeed on some VCPUs |
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* and not others, since it can involve hypervisor memory allocation, |
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* or because the guest failed to guarantee all the appropriate |
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* constraints on all VCPUs (ie buffer can't cross a page boundary). |
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* |
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* Note that any particular CPU may be using a placed vcpu structure, |
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* but we can only optimise if the all are. |
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* |
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* 0: not available, 1: available |
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*/ |
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int xen_have_vcpu_info_placement = 1; |
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static int xen_cpu_up_online(unsigned int cpu) |
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{ |
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xen_init_lock_cpu(cpu); |
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return 0; |
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} |
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int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), |
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int (*cpu_dead_cb)(unsigned int)) |
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{ |
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int rc; |
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rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, |
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"x86/xen/guest:prepare", |
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cpu_up_prepare_cb, cpu_dead_cb); |
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if (rc >= 0) { |
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rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, |
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"x86/xen/guest:online", |
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xen_cpu_up_online, NULL); |
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if (rc < 0) |
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cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); |
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} |
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return rc >= 0 ? 0 : rc; |
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} |
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static int xen_vcpu_setup_restore(int cpu) |
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{ |
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int rc = 0; |
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/* Any per_cpu(xen_vcpu) is stale, so reset it */ |
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xen_vcpu_info_reset(cpu); |
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/* |
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* For PVH and PVHVM, setup online VCPUs only. The rest will |
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* be handled by hotplug. |
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*/ |
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if (xen_pv_domain() || |
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(xen_hvm_domain() && cpu_online(cpu))) { |
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rc = xen_vcpu_setup(cpu); |
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} |
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return rc; |
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} |
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/* |
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* On restore, set the vcpu placement up again. |
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* If it fails, then we're in a bad state, since |
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* we can't back out from using it... |
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*/ |
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void xen_vcpu_restore(void) |
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{ |
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int cpu, rc; |
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for_each_possible_cpu(cpu) { |
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bool other_cpu = (cpu != smp_processor_id()); |
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bool is_up; |
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if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID) |
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continue; |
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/* Only Xen 4.5 and higher support this. */ |
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is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, |
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xen_vcpu_nr(cpu), NULL) > 0; |
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if (other_cpu && is_up && |
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HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL)) |
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BUG(); |
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if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) |
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xen_setup_runstate_info(cpu); |
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rc = xen_vcpu_setup_restore(cpu); |
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if (rc) |
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pr_emerg_once("vcpu restore failed for cpu=%d err=%d. " |
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"System will hang.\n", cpu, rc); |
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/* |
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* In case xen_vcpu_setup_restore() fails, do not bring up the |
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* VCPU. This helps us avoid the resulting OOPS when the VCPU |
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* accesses pvclock_vcpu_time via xen_vcpu (which is NULL.) |
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* Note that this does not improve the situation much -- now the |
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* VM hangs instead of OOPSing -- with the VCPUs that did not |
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* fail, spinning in stop_machine(), waiting for the failed |
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* VCPUs to come up. |
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*/ |
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if (other_cpu && is_up && (rc == 0) && |
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HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) |
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BUG(); |
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} |
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} |
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void xen_vcpu_info_reset(int cpu) |
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{ |
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if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) { |
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per_cpu(xen_vcpu, cpu) = |
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&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; |
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} else { |
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/* Set to NULL so that if somebody accesses it we get an OOPS */ |
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per_cpu(xen_vcpu, cpu) = NULL; |
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} |
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} |
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int xen_vcpu_setup(int cpu) |
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{ |
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struct vcpu_register_vcpu_info info; |
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int err; |
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struct vcpu_info *vcpup; |
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BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); |
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/* |
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* This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu) |
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* and at restore (xen_vcpu_restore). Also called for hotplugged |
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* VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm). |
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* However, the hypercall can only be done once (see below) so if a VCPU |
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* is offlined and comes back online then let's not redo the hypercall. |
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* |
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* For PV it is called during restore (xen_vcpu_restore) and bootup |
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* (xen_setup_vcpu_info_placement). The hotplug mechanism does not |
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* use this function. |
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*/ |
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if (xen_hvm_domain()) { |
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if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) |
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return 0; |
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} |
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if (xen_have_vcpu_info_placement) { |
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vcpup = &per_cpu(xen_vcpu_info, cpu); |
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info.mfn = arbitrary_virt_to_mfn(vcpup); |
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info.offset = offset_in_page(vcpup); |
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/* |
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* Check to see if the hypervisor will put the vcpu_info |
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* structure where we want it, which allows direct access via |
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* a percpu-variable. |
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* N.B. This hypercall can _only_ be called once per CPU. |
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* Subsequent calls will error out with -EINVAL. This is due to |
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* the fact that hypervisor has no unregister variant and this |
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* hypercall does not allow to over-write info.mfn and |
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* info.offset. |
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*/ |
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err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, |
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xen_vcpu_nr(cpu), &info); |
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if (err) { |
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pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n", |
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cpu, err); |
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xen_have_vcpu_info_placement = 0; |
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} else { |
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/* |
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* This cpu is using the registered vcpu info, even if |
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* later ones fail to. |
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*/ |
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per_cpu(xen_vcpu, cpu) = vcpup; |
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} |
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} |
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if (!xen_have_vcpu_info_placement) |
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xen_vcpu_info_reset(cpu); |
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return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0); |
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} |
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void xen_reboot(int reason) |
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{ |
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struct sched_shutdown r = { .reason = reason }; |
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int cpu; |
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for_each_online_cpu(cpu) |
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xen_pmu_finish(cpu); |
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if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) |
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BUG(); |
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} |
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static int reboot_reason = SHUTDOWN_reboot; |
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static bool xen_legacy_crash; |
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void xen_emergency_restart(void) |
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{ |
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xen_reboot(reboot_reason); |
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} |
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static int |
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xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) |
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{ |
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if (!kexec_crash_loaded()) { |
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if (xen_legacy_crash) |
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xen_reboot(SHUTDOWN_crash); |
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reboot_reason = SHUTDOWN_crash; |
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/* |
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* If panic_timeout==0 then we are supposed to wait forever. |
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* However, to preserve original dom0 behavior we have to drop |
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* into hypervisor. (domU behavior is controlled by its |
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* config file) |
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*/ |
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if (panic_timeout == 0) |
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panic_timeout = -1; |
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} |
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return NOTIFY_DONE; |
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} |
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static int __init parse_xen_legacy_crash(char *arg) |
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{ |
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xen_legacy_crash = true; |
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return 0; |
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} |
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early_param("xen_legacy_crash", parse_xen_legacy_crash); |
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static struct notifier_block xen_panic_block = { |
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.notifier_call = xen_panic_event, |
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.priority = INT_MIN |
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}; |
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int xen_panic_handler_init(void) |
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{ |
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atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); |
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return 0; |
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} |
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void xen_pin_vcpu(int cpu) |
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{ |
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static bool disable_pinning; |
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struct sched_pin_override pin_override; |
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int ret; |
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if (disable_pinning) |
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return; |
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pin_override.pcpu = cpu; |
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ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); |
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/* Ignore errors when removing override. */ |
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if (cpu < 0) |
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return; |
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switch (ret) { |
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case -ENOSYS: |
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pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", |
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cpu); |
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disable_pinning = true; |
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break; |
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case -EPERM: |
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WARN(1, "Trying to pin vcpu without having privilege to do so\n"); |
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disable_pinning = true; |
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break; |
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case -EINVAL: |
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case -EBUSY: |
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pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", |
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cpu); |
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break; |
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case 0: |
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break; |
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default: |
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WARN(1, "rc %d while trying to pin vcpu\n", ret); |
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disable_pinning = true; |
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} |
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} |
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#ifdef CONFIG_HOTPLUG_CPU |
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void xen_arch_register_cpu(int num) |
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{ |
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arch_register_cpu(num); |
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} |
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EXPORT_SYMBOL(xen_arch_register_cpu); |
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void xen_arch_unregister_cpu(int num) |
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{ |
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arch_unregister_cpu(num); |
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} |
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EXPORT_SYMBOL(xen_arch_unregister_cpu); |
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#endif
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